This application is the US national phase of international application PCT/EP2003/003149 filed 26 Mar. 2003 which designated the U.S. and claims benefit of DE 102 36 648.9, filed 9 Aug. 2002, the entire content of which is hereby incorporated by reference.
1. Technical Field
The invention relates to a fast-moving industrial gate with a gate body covering the gateway and having on either side a strap hinge with a multiplicity of hinge members that are interconnected such that they may be oriented at a relative angle, which are guided by rollers in lateral guides guiding the gate body free of contact.
2. Related Art
Fast-moving rolling gates employing coiling of the gate body above the gateway are known in practical use. These are, for example, rolling gates wherein a hanging of plasticized PVC or of a similar soft synthetic material is coiled on a coiling shaft in the customary manner and may be reeled off for closing the gateway. Such rolling gates were found to be excellently suited in practical use and are variously utilized as they may be furnished at low cost, and the gate body having the form of a hanging may moreover entirely or in parts be made transparent. Thus, e.g., the area on the other side of the gate body is also visible to a forklift driver, so that impediments or dangers may largely be avoided even if this rolling gate is to be passed through from both sides at the same time. It is another advantage of such plasticized PVC rolling gates that the gate body has a very low weight, so that the energy consumption for operating the gate may be kept low, and the dynamic loads during opening and closing of the gate are also limited. Therefore velocities of approx. 2 m/s are readily possible with the like rolling gates, so that they are also suited as a temporary closure between two consecutive passages.
The turns of the gate body having the form of a hanging in the case of such plasticized PVC rolling gates do, however, come to lie directly on each other in the coil and are accordingly scratched and soiled. Hereby the transparency of the hanging is degraded considerably in the course of time. Another drawback of these rolling gates is that this hanging, although usually held by the lateral edges in vertical guides, tends to bulge in the center region at higher wind forces owing to stretch of the material in the center region. From a certain wind load upwards, or even in the event of some other manual influence, the lateral edges of the hanging may come free from the vertical guides of the gateway. Damage to the hanging may then occur, and it moreover generally turns out to be problematic to reintroduce the hanging into the guides. It is a further drawback in such a plasticized PVC rolling gate that it moreover is usually not capable of being combined with a safety system in the manner of a gate light barrier as known, e.g., from DE 197 39 543 A and DE 197 39 544 A. The like gate light barriers generate accurately in the plane of closure of the gate a “light curtain” allowing to recognize obstacles free of contact, and thus avoid a collision. Owing to the flexibility and the thin wall of the hanging, however, this safety system can hardly be employed with such rolling gates including a flexible hanging, for the controls of the safety system detect the leading edge of the hanging and utilize it for recognizing an obstacle in the further path of closure of the gate.
Moreover from practical use a design for a rolling gate including a flexible hanging has become known, wherein several hanging segments are combined in order to form the flexible gate body. The edges of the hanging segments have a reinforcement strip-type configuration and each engage a respective connecting member coupling two hanging segments with each other. The hanging thus made up of several pieces is customarily coiled on a coiling shaft in the lintel. The arrangement of the connecting members within the hanging does, however, result in considerable irregularities that are of particular importance during the coiling process. This known rolling gate may therefore only be operated at a very low velocity of clearly less than one meter per second, and is moreover very noisy because clearly audible clattering noises occur when two connecting members meet in the coil. Such a rolling gate is generally not suited for fast-moving operation.
From practical use moreover a fundamentally different system for a fast-moving industrial gate is known, wherein a gate body formed of a multiplicity of aluminum lamellae that are interconnected such that they may be oriented at a relative angle is guided free of contact in the lintel range of the gateway. Thus the German patent applications DE 40 15 214 A, DE 40 15 215 A, and DE 40 15 216 A disclose a construction in which the lamellae of the gate body move with lateral rollers in guide rails. These are deflected at the top end of the gateway towards the inside of the gate into a straight guide section; following another downward deflection by 180 degrees they are again guided back in a straight line and then optionally again guided to the rear following a 180-degree upward deflection. This results in an elongate coil in which the lamellae of the gate body do, however, not lie on top of each other but are guided free of contact in a spaced-apart relation by the rollers in the guides. Lip seals are moreover arranged at the guides, which are contiguous with the gate body and thus establish a wind-tight closure for the gateway.
Another example for such a fast-moving industrial gate is known from DE 199 15 376 A1, wherein the lamellae are formed of extruded plastic and may be made transparent completely or only in a partial area. As these lamellae are formed of GRP or PMMA, for instance, they have a lower weight in comparison with conventional lamellae of aluminum. The use of these plastic lamellae of a pliant material is made possible, in accordance with this known industrial gate, in that the lamellae in the range of the gate lintel move into a spiral section having a continuously curved spiral shape, so that the dynamic loads of the gate body can be kept within limits. This industrial gate has been found to be very advantageous for many applications in practical use. Thus it is possible to reliably achieve high velocities of up to 3 m/s, while it is at the same time also possible to make the gate body substantially continuously transparent.
This industrial gate with plastic lamellae does, however, also suffer from drawbacks. Namely, these lamellae have such a low strength in comparison with aluminum lamellae that they are hardly suited for gate widths exceeding four meters. In addition, these plastic lamellae have a shorter lifetime than conventional aluminum lamellae. In particular it has been found that from a certain gate size upward, cracks may develop in the range in which the strap hinges are fastened to the lamellae. Another drawback in this design lies in the fact that the lamellae are extruded as a whole, so that there are limits to variation in terms of material. In particular the provision of these lamellae is connected with a considerable expense in terms of production technology and therefore relatively expensive. Moreover it is not possible to modify the constructional shape of the lamella without considerable expense; this requires the production of a new extrusion die for each case. Furthermore the transparent area in this known plastics lamella is not clear as glass owing to the production process, as in particular small but clearly recognizable processing traces in the direction of extrusion are unavoidable.
On the other hand the fast-moving industrial gate in accordance with DE 199 15 376 A1 is characterized by its capability of sustaining high wind loads, exemplary tightness, model reliability and high availability. Nevertheless in practice an even faster and yet affordable system is being demanded, which does, however, manage without any reductions of the advantageous properties of the known gate systems.
From U.S. Pat. No. 2,311,470 another gate closure in the manner of a lamellar shield is known, the gate body of which includes on either side a strap hinge with a multiplicity of hinge members that are interconnected such that they may be oriented at a relative angle, which are guided by rollers in lateral guides guiding the gate body free of contact. The gate body comprises a multiplicity of lamellae interconnected by means of rigid, semi-rigid, or flexible connecting strips which are affixed on the mutually facing longitudinal edges of the lamellae in positive engagement. Moreover the single lamellae extend transversely to the lateral guides across the gate body to thereby connect two respective associated hinge members.